Synthesis and Characterization of Bifunctional Organic-Glasses Based on Diphenylhydrazone and Barbituric Acid Derivative for Photorefractive Application

A series of amorphous molecules that possess both photoconductive and electro-optic properties was synthesized in order to investigate photorefractive properties of bifunctional organic-glasses. Diethylaminobenzaldehyde-diphenylhydrazone was covalently attached to 5-(4-diethylamino-benzylidene)d,3-dimethyl-pyrimidine-2,4,6-trione through a flexible alkyl chain (3, 4, 5, 6 and 10 carbons) containing two ether linkages. The longer linkage not only lowered the glass transition temperature (T _g) of the molecules, but also allowed faster orientation of the chromophore. To examine the photorefractive properties, a 50 μm-thick film was prepared from the mixture of a bifunctional molecule, butyl benzyl phthalate, and C₆₀. The photoconductivity of this composite was as high as 8.01 × 10^-12 S/cm at 60 V/μm, and the maximum diffraction efficiency (ηmax) of 50 μm-thick film was about 5% at 80 V/μm.